Fuel Injection Control During Start-Up

ABSTRACT

A method of operation of an internal combustion engine including an intake valve coupled to a combustion chamber, and a port fuel injector positioned upstream of the intake valve in an intake manifold including a throttle, the port fuel injector fluidly coupled to a fuel rail included in a fuel delivery system housing a fuel at least partially composed of alcohol. The method including, during a start-up operation when the temperature of the engine is below a threshold value and fuel is actively being injected into the intake manifold, adjusting a cone angle of a fuel spray from the port fuel injector, via adjustment of the throttle and/or fuel delivery system, based on the position of the intake valve.

BACKGROUND AND SUMMARY

Various fuel injection approaches may be used in internal combustionengines. However, wall wetting has slowed efforts to improve fuelinjection performance and combustion efficiency. In particular, undercertain operating conditions wall wetting may lead to bore wash, therebyincreasing combustion inefficiencies and degrading engine components,such as pistons, piston rings, etc., leading to increased emissions aswell as increased repair costs. Additionally, wall wetting may alsoincrease fuel loss during valve overlap when fuel travels into theexhaust passage from the intake manifold, increasing emissions anddecreasing engine efficiency. Moreover, the use of alcohol within thefuel delivery system may exacerbate fuel loss during valve overlap aswell as bore wash, further degrading engine operation.

It has been found that during various operating conditions engineperformance may be increased by varying the angle of a fuel spray conefrom a port fuel injector. U.S. Pat. No. 7,043,350 discloses a system inwhich the temperature of the fuel injector is altered to adjust the coneangle of the fuel spray. The angle of the fuel spray cone, delivered viaa fuel injector, is adjusted by a heating device. Specifically, thetemperature of the fuel injected may be adjusted via a heater directlycoupled to the fuel injector.

However, the inventors herein have recognized several disadvantages withsuch an approach. The heater may increase the servicing and repair costsof the engine. Moreover, the size of the fuel spray cone may be limitedby the ambient temperature. The limited spray cone size may becomeparticularly problematic during cold-starts. For example, during acold-start the spray cone size cannot be reduced beyond a thresholdvalue proportional to the ambient temperature, leading to increased borewash, fuel loss during valve overlap, and combustion inefficiencies.

In one approach, the above issues may be addressed by a method ofoperation of an internal combustion engine including an intake valvecoupled to a combustion chamber, and a port fuel injector positionedupstream of the intake valve in an intake manifold including a throttle,the port fuel injector fluidly coupled to a fuel rail included in a fueldelivery system housing a fuel at least partially composed of alcohol.The method may include, during a start-up operation when the temperatureof the engine is below a threshold value and fuel is actively beinginjected into the intake manifold, adjusting a cone angle of a fuelspray from the port fuel injector, via adjustment of the throttle and/orfuel delivery system, based on the position of the intake valve (e.g.,based on whether the fuel injection is open intake valve fuel injectionor closed intake valve fuel injection).

In one example, the method includes decreasing the cone angle duringopen valve injection. By decreasing the cone angle during open valveinjection, the wall wetting within the combustion chamber and the intakemanifold may be decreased, thereby decreasing bore wash as well as fuelloss during valve overlap. In this way, wear on various enginecomponents, such as the combustion chamber, piston, seals, etc., as wellas the emissions from the vehicle may be reduced. Furthermore, bydecreasing the cone angle of the fuel spray during engine start-upoperation, the vaporization of the fuel during combustion (e.g. thepower stroke) may be increased due to the increased charge densitywithin the combustion chamber. Thus, the efficiency of the engine may beincreased when the spray cone angle is reduced.

As another example, the method may include decreasing the cone angleduring closed valve injection. Therefore, by decreasing the cone angleduring closed valve injection, the fuel puddle may be localized to thevalve seat, thereby decreasing wall wetting, leading to theaforementioned benefits (e.g. decreased fuel loss during valve overlapand engine wear).

As yet another example, the cone angle of the cone angle may bealternatively and/or additionally adjusted based on an alcohol contentof the fuel. Specifically, during engine starting, the cone angle may bedecreased as the percentage or amount of alcohol in the fuel isincreased. Therefore, the increased wall wetting caused by the alcoholmay be mitigated by decreasing the cone angle, decreasing wear on enginecomponents and fuel loss during valve overlap.

It should be understood that the background and summary above isprovided to introduce in simplified form a selection of concepts thatare further described in the detailed description. It is not meant toidentify key or essential features of the claimed subject matter, thescope of which is defined uniquely by the claims that follow thedetailed description. Furthermore, the claimed subject matter is notlimited to implementations that solve any disadvantages noted above orin any part of this disclosure. Further, the above issues and relatedapproaches have been recognized by the inventors herein, and noadmission is made as to whether such information is known to thoseskilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an internal combustion engine.

FIG. 2A illustrates a detailed view of the combustion chamberillustrated in FIG. 1 and a fuel delivery system.

FIG. 2B illustrates a detailed view of the fuel injector shown in FIG.2A.

FIGS. 3A-3C show various fuel injection and fuel spray cone adjustmentstrategies which may be implemented during start-up.

FIG. 4 illustrates a method that may be used during start-up to reducewall wetting.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram showing one cylinder of multi-cylinderengine 10, which may be included in a propulsion system of anautomobile. Engine 10 may be controlled at least partially by a controlsystem including controller 12 and by input from a vehicle operator 132via an input device 130. In this example, input device 130 includes anaccelerator pedal and a pedal position sensor 134 for generating aproportional pedal position signal PP. Combustion chamber (i.e.cylinder) 30 of engine 10 may include combustion chamber walls 32 withpiston 36 positioned therein. Piston 36 may be coupled to crankshaft 40so that reciprocating motion of the piston is translated into rotationalmotion of the crankshaft. Crankshaft 40 may be coupled to at least onedrive wheel of a vehicle via an intermediate transmission system.Further, a starter motor may be coupled to crankshaft 40 via a flywheelto enable a starting operation of engine 10.

Combustion chamber 30 may receive intake air from intake manifold 44 viaintake passage 42 and may exhaust combustion gases via exhaust passage48. Intake manifold 44 and exhaust passage 48 can selectivelycommunicate with combustion chamber 30 via respective intake valve 52and exhaust valve 54. In some embodiments, combustion chamber 30 mayinclude two or more intake valves and/or two or more exhaust valves. Ina multi-cylinder engine the intake manifold may be fluidly coupled to aplurality of intake ports.

In this example, intake valve 52 and exhaust valves 54 may be controlledby cam actuation via respective cam actuation systems 51 and 53. Camactuation systems 51 and 53 are depicted in a double overhead cam-shaftconfiguration. However, in other examples alternate cam-shaftconfigurations may be utilized, such as a single overhead cam-shaftconfiguration. Cam actuation systems 51 and 53 may each include one ormore cams and may utilize one or more of cam profile switching (CPS),variable cam timing (VCT), variable valve timing (VVT) and/or variablevalve lift (VVL) systems that may be operated by controller 12 to varyvalve operation. The position of intake valve 52 and exhaust valve 54may be determined by position sensors 55 and 57, respectively. Inalternative embodiments, intake valve 52 and/or exhaust valve 54 may becontrolled by electric valve actuation. For example, cylinder 30 mayalternatively include an intake valve controlled via electric valveactuation and an exhaust valve controlled via cam actuation includingCPS and/or VCT systems.

Fuel injector 66 is shown arranged in intake manifold 44 in aconfiguration that provides what is known as port injection of fuel intothe intake port upstream of combustion chamber 30. In some examples,multi-point fuel injection may be utilized. Fuel injector 66 may injectfuel in proportion to the pulse width of signal FPW received fromcontroller 12 via electronic driver 68. Fuel may be delivered to fuelinjector 66 via a fuel delivery system 200, including a fuel tank 202, afuel pump 204, and a fuel rail 210, schematically illustrated in FIG.2A, discussed in greater detail herein. In some embodiments, combustionchamber 30 may alternatively or additionally include a fuel injectorcoupled directly to combustion chamber 30 for injecting fuel directlytherein, in a manner known as direct injection.

Returning to FIG. 1, intake passage 42 may include a throttle 62 havinga throttle plate 64. In this particular example, the position ofthrottle plate 64 may be varied by controller 12 via a signal providedto an electric motor or actuator included with throttle 62, aconfiguration that is commonly referred to as electronic throttlecontrol (ETC). In this manner, throttle 62 may be operated to vary theintake air provided to combustion chamber 30 among other enginecylinders. The position of throttle plate 64 may be provided tocontroller 12 by throttle position signal TP. Intake passage 42 mayinclude a mass air flow sensor 120 and a manifold air pressure sensor122 for providing respective signals MAF and MAP to controller 12.Ignition system 88 can provide an ignition spark to combustion chamber30 via spark plug 92 in response to spark advance signal SA fromcontroller 12, under select operating modes. Though spark ignitioncomponents are shown, in some embodiments, combustion chamber 30 or oneor more other combustion chambers of engine 10 may be operated in acompression ignition mode, with or without an ignition spark.

Exhaust gas sensor 126 is shown coupled to exhaust passage 48 upstreamof emission control device 70. Sensor 126 may be any suitable sensor forproviding an indication of exhaust gas air/fuel ratio such as a linearoxygen sensor or UEGO (universal or wide-range exhaust gas oxygen), atwo-state oxygen sensor or EGO, a HEGO (heated EGO), a NOx, HC, or COsensor. Emission control device 70 is shown arranged along exhaustpassage 48 downstream of exhaust gas sensor 126. Device 70 may be athree way catalyst (TWC), NOx trap, various other emission controldevices, or combinations thereof. In some embodiments, during operationof engine 10, emission control device 70 may be periodically reset byoperating at least one cylinder of the engine within a particularair/fuel ratio.

Controller 12 is shown in FIG. 1 as a microcomputer, includingmicroprocessor unit 102, input/output ports 104, an electronic storagemedium for executable programs and calibration values shown as read onlymemory chip 106 in this particular example, random access memory 108,keep alive memory 110, and a data bus. Controller 12 may receive varioussignals from sensors coupled to engine 10, in addition to those signalspreviously discussed, including measurement of inducted mass air flow(MAF) from mass air flow sensor 120; engine coolant temperature (ECT)from temperature sensor 112 coupled to cooling sleeve 114; a profileignition pickup signal (PIP) from Hall effect sensor 118 (or other type)coupled to crankshaft 40; throttle position (TP) from a throttleposition sensor; and absolute manifold pressure signal, MAP, from sensor122. Engine speed signal, RPM, may be generated by controller 12 fromsignal PIP. Manifold pressure signal MAP from a manifold pressure sensormay be used to provide an indication of vacuum, or pressure, in theintake manifold. Note that various combinations of the above sensors maybe used, such as a MAF sensor without a MAP sensor, or vice versa.During stoichiometric operation, the MAP sensor can give an indicationof engine torque. Further, this sensor, along with the detected enginespeed, can provide an estimate of charge (including air) inducted intothe cylinder. In one example, sensor 118, which is also used as anengine speed sensor, may produce a predetermined number of equallyspaced pulses every revolution of the crankshaft.

As described above, FIG. 1 shows only one cylinder of a multi-cylinderengine, and that each cylinder may similarly include its own set ofintake/exhaust valves, fuel injector, spark plug, etc.

FIG. 2A illustrates a detailed view of the combustion chamber andassociated fuel delivery system 200 included in internal combustionengine 10, illustrated in FIG. 1. In particular, an intake valve seat220 is depicted in FIG. 2A. The intake valve seat may include thesurface against which the intake valve rests while the valve is in aclosed position and in which fluidic communication between thecombustion chamber and intake manifold is substantially decreased.

Fuel delivery system 200 may include a fuel tank 202 at least partiallyenclosing a pump 204. In some examples, pump 204 may be anelectronically actuated lift pump. However, in other examples, pump 204may be another suitable type of pump, such as a mechanically drivenpump, a rotodynamic pump, etc. Pump 204 may be electronically coupled tocontroller 10, illustrated in FIG. 1. Continuing with FIG. 2A, a fuelfilter 206 may be coupled to the pump via a fuel line 208. The fuelfilter may be configured to remove unwanted particulates from the fuel.A fuel rail 210 may be coupled to the fuel filter via a fuel line 212.Likewise, fuel injector 66 may be coupled to the fuel rail. It will beappreciated that fuel rail 210 may be configured to delivery fuel to aplurality of port fuel injectors included in a multi-cylinder engine.Fuel injector 66 may be configured to deliver a fuel spray 213 into theintake manifold (e.g. intake port) during certain operating conditions.

Additional or alternate components may be included in the fuel deliverysystem. The components may include but are not limited to a mechanicallyactuated pump (not shown) positioned downstream of the lift pump, one ormore check valves (not shown) positioned downstream of the lift pump,one or more solenoid valves (not shown) coupled downstream of the liftpump, a return-less fuel circuit (not shown) fluidly coupled downstreamof the lift pump and to the fuel tank, etc.

In this example, the fuel utilized in fuel delivery system 200 may bepartially composed of an alcohol. As one example, the fuel deliverysystem and therefore the engine, can utilize E85 which includes amixture of approximately 85% ethanol and 15% gasoline. Still otherengines may be configured as a flex-fuel engines, whereby a plurality ofdifferent fuel mixtures may be used by the engine. For example, aflex-fuel engine may be configured to utilize a variety of differentblends of ethanol and gasoline including up to 100% gasoline, E10 whichincludes approximately 10% ethanol and 90% gasoline, and up to 100%ethanol. Thus, engines can utilize a variety of different fuel mixtures.Alternatively, other fuels such as methanol, diesel, hydrogen,biodiesel, etc., may be used. It will be appreciated that under certainconditions, such as during cold starts, wall wetting of the combustionchamber and/or the intake manifold may be exacerbated when a fuel havinga greater alcohol concentration is utilized in the fuel delivery system.Wall wetting may include the substantial adherence and/or impingement ofa fuel spray upon the walls of the combustion chamber and/or the intakemanifold, particularly during open intake valve injection. An openintake valve may include an intake valve which is not seated and sealedon a valve seat, allowing the combustion chamber to be in fluidiccommunication with the intake manifold.

FIG. 2B shows a detailed view of fuel injector 66. In this example, thefuel injector includes a main body 214, a nozzle 216, and a valve 218.The nozzle may be configured to deliver fuel spray 213, which may be inthe shape of cone, into intake manifold 44. The fuel spray has an angleθ. It will be appreciated that in other examples, alternate nozzleshaving alternate spray patterns may be used to deliver fuel into theintake manifold, such as a flat spray pattern, a hollow spray pattern, amulti-cone spray pattern, etc. Due to the characteristics of the fuelinjector a change in the pressure differential across the fuel injectormay alter the angle θ, such as the cone angle of the fuel spray. Forexample, as the pressures differential is decreased, the cone angle mayalso be decreased. Thus, the cone angle of the fuel spray may beadjusted via an adjustment of the pressure differential across the fuelinjector.

The pressure differential across the fuel injector may be altered viaadjustment of the MAP and/or the fuel rail pressure, depending onoperating conditions in the vehicle, such as fuel composition, intakevalve position, engine temperature, ambient temperature, injectiontiming, etc. Under certain operating conditions, such as when the intakevalve is in an open position during fuel injection, the throttle may beadjusted to alter the MAP, thereby adjusting the angle θ of the fuelspray. Additionally or alternatively, the fuel rail pressure may beadjusted to alter the angle θ of the fuel spray. Specifically, the fuelrail pressure may be adjusted via adjustment of fuel delivery systemcomponents, such as the lift pump and/or one or more valves.

The temperature of the fuel, and therefore the temperature of the fuelinjector, may also affect the angle θ of the fuel spray. In the past,attempts have been made to heat the fuel via a fuel injector heatingsystem to adjust angle of the fuel spray, such as the cone angle.However, due to the increased cost of a fuel injection heating system aswell as the increased load applied to the electrical system, the fuelinjection heating system may not be included internal combustion engine10. Therefore, to adjust the cone angle the pressure differential acrossthe fuel injector may be adjusted utilizing existing system components(e.g. the throttle and/or the fuel delivery system), as discussed above,reducing system cost. Additionally, when a fuel injection heating systemis not included in the engine the amount of energy available to thestarter motor is increased, thereby increasing the amount of energywhich can be delivered to the combustion chamber during start-up,increasing combustion efficiency. However, a fuel injector heatingsystem may be used in addition to the techniques noted herein, ifdesired.

FIGS. 3A-3C illustrate various graphical depictions of fuel injectionstrategies which may be utilized during a start-up operation. In someexamples, the start-up operation may be a cold-start. Various fuel spraycone angle adjustment strategies may be carried out during a fuelinjection event during engine start-up. It will be appreciated thatalternate fuel spray angles may be adjusted, in other examples.Selection of the fuel injection strategy and spray cone adjustmentstrategy may depend on various parameters which may include but are notlimited to the position and/or actuation timing of the intake valveand/or exhaust valve, fuel composition, engine temperature, torquerequest, ambient temperature, MAP, injection timing, etc.

In the Figures, the y-axis represents the intake valve's position, thex-axis represents time, and the fuel injection events are represented at310, 312, and 314. The following metrics may be used to characterize afuel injection event: injection timing, injection amplitude, and fuelpulse width.

FIG. 3A illustrates a closed intake valve injection in which a fuelinjection event 310 is executed substantially while the intake valve isclosed. In this example, various cone angle adjustment strategies may becarried out during the closed intake valve injection. In particular,during the closed intake valve injection of an engine start-up (e.g.,including engine cranking, engine run-up, the fuel rail pressure may bedecreased via a fuel delivery system adjustment (e.g. lift pumpadjustment and/or valve adjustment), to decrease the cone angle.Additionally or alternatively, the MAP may be increased via a throttleadjustment, to decrease the cone angle, until the engine has completed aselected number of combustion events, or until a preselected enginespeed or engine temperature has been reached. For example, the throttlemay be opened to a greater degree or alternatively may be inhibited fromclosing, to increase the MAP and decrease the cone angle of the fuelspray. It will be appreciated that in some examples, the fuel deliverysystem and the throttle may be correspondingly adjusted to achieve adesired or selected cone angle. Thus, in some examples, the fuel railpressure and the MAP may be adjusted at concurrent or overlapping timeintervals during the fuel injection event.

Due to the characteristics of the fuel injector, when the cone angle ofthe fuel spray is decreased, during a closed intake valve injection, thefuel puddle may be substantially localized on the valve and/or the valveseat. Therefore, the total fuel puddle mass as well as the fuel sprayimpingement upon the walls of the intake manifold (e.g. intake port) maybe reduced, thereby decreasing the amount of fuel which travels into theexhaust passage from the intake manifold during valve overlap. Valveoverlap may include a time interval during which the intake valve andthe exhaust valve are at least partially open and both the intakemanifold and the exhaust passage are in fluidic communication with thecombustion chamber.

Additionally, under certain operating conditions, bore wash within thecombustion chamber during start-up may be reduced when the sprayimpingement upon the walls of the intake manifold is reduced, therebyreducing total fuel puddle mass. Thus, the emissions from the vehicle aswell as the wear on various engine components may be reduced when thecone angle is reduced during start-up (whereas the cone angle may bereturned to its nominal value (increased) after the start-up operation).Consequently, the size of the cone angle may be selected based on thegeometry of the intake manifold as well as the intake valve. Additionalparameters which may be used to select the spray cone angle include theposition and/or timing of the intake valve, engine temperature, ambienttemperature, the fuel composition, and/or the MAP. In particular, thecone angle may be selected such that the fuel spray cone is localized tothe valve and/or the valve seat during a closed intake valve injectionduring start-up, in some examples. In this way, fuel loss during valveoverlap and/or bore wash within the combustion chamber may be decreasedduring start-up.

FIG. 3B depicts an open intake valve injection in which a fuel injectionevent 312 is executed substantially while the intake valve is open,allowing at least a portion fuel to be sprayed directly into thecombustion chamber. In this example, various cone angle adjustmentstrategies may be carried out during the open valve injection.Specifically, during engine starting, the fuel rail pressure may bedecreased to decrease the cone angle, thereby decreasing the fuel sprayimpingement upon the walls of the intake manifold (e.g. intake port)and/or the walls of the combustion chambers. Then, after a predeterminednumber of combustion events, or after engine speed rises to a selectedthreshold, for example, the cone angle may be increased, or returned toits nominal value. The fuel rail pressure may be decreased via a fueldelivery system adjustment (e.g. lift pump adjustment and/or valveadjustment), as described above. Additionally or alternatively, the MAPmay be increased via throttle adjustment to decrease the cone angle, asdescribed above. The increased MAP may not substantially affect the fuelloss during valve overlap due to the decreased fuel spray impingement(e.g. low fuel puddle mass) upon the walls of the intake manifold.Therefore, when the cone angle of the fuel spray is decreased during anopen valve injection, the fuel losses during valve overlap and/or wallwetting within the combustion chamber may be reduced. Reduced wallwetting within the combustion chamber may lead to decreased bore wash.

It has been found through experimentation that increasing the MAP duringan open valve injection increases the trapped mass in the combustionchamber during a subsequent compression stroke. Therefore, increasingthe trapped mass within the combustion chamber increases the chargedensity, providing increased fuel vaporization during combustion as wellas increased combustion temperatures. Consequently, when the MAP isincreased during start-up the combustion efficiency is increased.

In some examples, the magnitude of the cone angle adjustment during anopen valve injection may be disproportionate to the magnitude of thecone angle adjustment during a closed valve injection. For example,during an open valve injection the cone angle may be decreased to agreater extent than during a closed valve injection or visa-versa.However, in other examples the magnitude of the cone angle adjustmentduring an open and a closed intake valve injection may be substantiallyequivalent. Further, a degree of cone angle decrease during enginestarting may depend on ambient temperature (where more of a decrease isprovided at colder temperatures).

Additionally, FIG. 3C illustrates a fuel injection event 314 that isexecuted during a time interval while the intake valve is closed andthen subsequently opened. In this example, during fuel injection event314, the fuel rail pressure may be decreased via an adjustment of thefuel delivery system, as described above, to decrease the cone angle ofthe fuel spray, thereby decreasing the impingement of the fuel sprayupon the walls of the intake manifold (e.g. intake port) and/or thewalls of the combustion chamber. Additionally or alternatively, the MAPmay be increased via throttle adjustment, as described above, todecrease the cone angle of the fuel spray. The cone angle of the fuelspray may be selected based on one or more of the following parameters:the position and/or timing of the intake valve, engine temperature,ambient temperature, the fuel composition, the MAP, and the enginetemperature.

In some examples the magnitude of the cone angle adjustment during afuel injection event in which the intake valve is closed andsubsequently opened may be disproportionate to the open and/or closedintake valve injections. However, in other examples the magnitude of thecone angle adjustment during a fuel injection event in which the intakevalve is closed as subsequently opened may be substantially proportionalto the magnitude of the cone angle adjustment during an open and/orclosed intake valve injection. It will be appreciated that theaforementioned control strategies are exemplary in nature, and amultitude of control strategies may be used during start-up to adjustthe cone angle of the fuel spray.

Furthermore, when a fuel at least partially composed of alcohol is usedin the fuel delivery system, bore wash within the cylinder as well asfuel loss during valve overlap may be increased, during certainoperating conditions (e.g. cold-start), due to the fuel impingement uponthe walls of the intake manifold and/or the combustion chamber. Inparticular, as the amount or percentage of alcohol in the fuel isincreased bore wash and fuel loss is further exacerbated for variousreasons, such as the fuel volatility, the degrading effects of alcoholon engine oil, etc. Therefore, in some examples, the cone angle of thefuel spray may be reduced as the amount or percentage of the alcohol inthe fuel is increased, to decrease fuel loss during valve overlap aswell as bore wash. In this way, the engine operation may be improved,decreasing emissions and engine wear as well as increasing efficiency.

Additionally, as the engine temperature (e.g. cylinder temperature)increases, the cone angle of the fuel spray may have less of an effecton wall wetting, due to the increased vaporization of the fuel.Furthermore, as the MAP is drawn down, subsequent to start-up, the fuelloss during valve overlap may be decreased. Therefore, when thetemperature of the engine and/or the MAP reaches a threshold value, thecone angle of the fuel spray may be increased. In some examples, thecone angle of the fuel spray may be increased when a negative pressurebalance between the intake manifold and the exhaust passage is reached.Additionally or alternatively, the fuel spray cone angle may beincreased when the engine has completed a pre-determined number ofcombustion cycles, subsequent to start-up.

FIG. 4 shows a method 400, which may implemented to adjust the coneangle of the fuel spray from a port fuel injector during start-up. Insome examples, method 400 may be implemented utilizing the systems andcomponents, described above. Alternatively, in other examples, method400 may be implemented utilizing other suitable systems and components.

At 410 the method may include initiating start-up operation. One or moreof the following actions may be carried out to initiate start-upoperation: actuating an ignition apparatus (e.g. rotation of an ignitionkey), powering a controller, powering a starter motor, initiating acrank-start sequence, starting the engine from rest, etc. Next, at 412,it may be determined if the engine is below a threshold temperature. Thethreshold temperature may be calculated utilizing one or more of thefollowing parameters: fuel composition, ambient temperature, andatmospheric pressure. In some examples, method 400 may be implementedduring a cold-start operation when the ambient temperature isapproaching the engine temperature. Further in other examples, step 412may not be included in method 400.

If the engine is not below a threshold temperature the method ends.However, if the engine is below a threshold temperature, it may bedetermined, at 414, if the MAP is above a threshold value. The thresholdMAP may be calculated based on one or more of the following parameters:exhaust passage pressure, ambient temperature, and atmospheric pressure.However, in other examples step 414 may not be included in the method.Further in other examples, it may be determined if the total number ofcombustion cycles performed after start-up have surpassed a thresholdvalue.

If it is determined that the MAP is not above a threshold value themethod ends. However, if it is determined that the MAP is above athreshold value, the method proceeds to 416 where the composition of thefuel is determined.

Next, the method advances to 417, where a fuel injection event isinitiated, upstream of the intake valve from a port fuel injector. Itwill be appreciated that in some examples steps 418-420 may beimplemented during the fuel injection event. Next, method 400 proceedsto 418, where the MAP is adjusted based on fuel composition and/or aposition of the intake valve, to decrease the cone angle of the fuelspray, thereby decreasing wall wetting within the intake passage and/orthe combustion chamber. The MAP may be altered via throttle adjustment,at 418 a. In some examples, the MAP may be adjusted based on the amountor percentage of alcohol contained within the fuel. Specifically, theMAP may be increased as the percentage of alcohol in the fuel isincreased or visa-versa. In this way, the bore wash caused by thealcohol in the fuel may be decreased. Still further in other examples,the MAP may be adjusted based on the position of the intake valve. Inparticular, the MAP may be increased to a greater degree during an openvalve injection when compared to a closed valve injection or visa-versa.

After 418 the method may also proceed to 420, where the fuel pressurewithin the fuel delivery system is adjusted based on the fuelcomposition and/or the position of the intake valve, to decrease wallwetting within the intake manifold and/or combustion chamber. Adjustmentof the fuel pressure may include at 420 a, adjusting one or more pumpswithin the fuel delivery system and at 420 b, adjusting one or morevalves within the fuel delivery system. In some examples, the fuelpressure within the fuel delivery may be decreased based on the alcoholcomposition of the fuel. Specifically, the fuel pressure in the fueldelivery system (e.g. fuel rail pressure) may be decreased as thepercentage of alcohol in the fuel is increased or visa-versa.Furthermore, the fuel pressure may be adjusted based on the position ofthe intake valve. For example, the fuel pressure may be decreased to agreater extent during an open valve injection when compared to a closedvalve injection or visa-versa.

Next, in some examples, method 400 may proceed to 422, where it isdetermined if the engine is above a threshold temperature. Alternativelyor additionally, it may be determined if the engine has reached athreshold MAP. The threshold temperature and/or MAP may be calculatedbased on one or more of the following parameters: ambient temperature,fuel composition, requested torque, air-fuel ratio, exhaust pressure,exhaust gas temperature, and valve timing. Still further in alternate oradditional examples, it may be determined if a threshold number ofcombustion cycles, which may be predetermined, have occurred subsequentto the initiation of start-up operation.

If it is determined that the engine is not above a threshold temperaturethe method may return to 422. However, if it is determined that theengine is above a threshold temperature method 400 may advance to 424,where the cone angle of the fuel spray is increased. Increasing the fuelspray cone angle may include discontinuing the MAP and/or fuel pressureadjustments at 424 a. For example, the MAP may be decreased and/or thefuel pressure (e.g. fuel rail pressure) within the fuel delivery systemmay be increased, thereby increasing the cone angle of the fuel spray.

The system and method described above allows the wall wetting within theintake manifold and/or combustion chamber to be decreased duringstart-up, thereby decreasing fuel losses during valve overlap, as wellas bore wash, in some examples. In this way, the longevity of variousengine components and engine performance may be increased.

Note that the example control and estimation routines included hereincan be used with various engine and/or vehicle system configurations.The specific routines described herein may represent one or more of anynumber of processing strategies such as event-driven, interrupt-driven,multi-tasking, multi-threading, and the like. As such, various acts,operations, or functions illustrated may be performed in the sequenceillustrated, in parallel, or in some cases omitted. Likewise, the orderof processing is not necessarily required to achieve the features andadvantages of the example embodiments described herein, but is providedfor ease of illustration and description. One or more of the illustratedacts or functions may be repeatedly performed depending on theparticular strategy being used. Further, the described acts maygraphically represent code to be programmed into the computer readablestorage medium in the engine control system.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to V-6,I-4, I-6, V-12, opposed 4, and other engine types. The subject matter ofthe present disclosure includes all novel and nonobvious combinationsand subcombinations of the various systems and configurations, and otherfeatures, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations andsubcombinations regarded as novel and nonobvious. These claims may referto “an” element or “a first” element or the equivalent thereof. Suchclaims should be understood to include incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.Other combinations and subcombinations of the disclosed features,functions, elements, and/or properties may be claimed through amendmentof the present claims or through presentation of new claims in this or arelated application. Such claims, whether broader, narrower, equal, ordifferent in scope to the original claims, also are regarded as includedwithin the subject matter of the present disclosure.

1-20. (canceled)
 21. A method or operating an engine including a portfuel injector, comprising: during a start-up operation when enginetemperature is below a threshold, manifold pressure is above a pressurethreshold, and the injector actively injects fuel with an open intakevalve, decreasing a fuel spray cone angle from the injector; and thenincreasing the cone angle after a selected number of combustion events,the cone angle further adjusted based on a fuel alcohol content.
 22. Themethod according to claim 21 wherein the cone angle is reduced as anamount of alcohol in the fuel is increased
 23. The method according toclaim 21 wherein the start-up operation includes a crank-start sequence.24. A method of operating an engine including a fuel injector,comprising: during a start-up operation when engine temperature is belowa threshold value and before manifold pressure is pumped down below apressure threshold, during active injection of fuel by the injector, andduring intake to exhaust valve overlap conditions with both the intakeand exhaust valve open, decreasing a fuel spray cone from the injector,where an amount of decrease is based on alcohol content of the fuel; andthen subsequent to start-up operation, increasing the fuel spray conefrom the injector.
 25. The method according to claim 24 wherein fuelrail pressure is adjusted during engine operation.
 26. The methodaccording to claim 25 wherein the throttle is adjusted to increase amanifold air pressure.
 27. The method according to claim 24 furthercomprising decreasing the fuel spray cone angle for higher alcoholcontent of the fuel.
 28. The method according to claim 24 wherein a fuelrail pressure is decreased via actuation of one or more pumps and/orvalves within the fuel delivery system, to decrease the cone angle.